Bone marrow transplantation (BMT) offers great promise for the treatment of a number of chronic disease states, including autoimmunity, organ tolerance, and the hemoglobinopathies. Widespread clinical application of this approach, however, is dependent upon the development of methods to establish and maintain chimerism and avoid graft-versus-host disease (GVHD).
Facilitating cells (FCs) are a CD8+/TCR− bone marrow subpopulation that enhance engraftment of purified hematopoietic stem cells (HSC) in allogeneic recipients without causing GVHD. FCs also potently enhance engraftment of suboptimal numbers of HSC in syngeneic recipients. Therefore, approaches to expand FC numbers and enhance their function could have a significant impact upon the use of BMT in treating nonmalignant disorders, especially when HSC numbers are limiting such as in cord blood transplantation.